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 * The Universal Permissive License (UPL), Version 1.0
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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package com.oracle.graal.python.builtins.objects.cext.common;

import com.oracle.graal.python.runtime.PythonContext;
import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;

/**
 * This class can be used to bridge between JNI and LLVM. In particular, we use it to wrap native
 * pointers received from JNI. In this way, the pointers can be used with code written for LLVM.
 * Ultimately, this class should go away once JNI and LLVM backends are untangled.
 */
@ExportLibrary(InteropLibrary.class)
public final class NativePointer implements TruffleObject {
    private final long ptr;

    public NativePointer(long ptr) {
        /*
         * Instances of this type may only be created if native access is allowed because other code
         * relies on that and may use Unsafe without further checking.
         */
        assert PythonContext.get(null).getEnv().isNativeAccessAllowed();
        this.ptr = ptr;
    }

    private NativePointer() {
        this.ptr = 0;
    }

    /**
     * Returns an object representing a {@code NULL} pointer. This may also be used if
     * {@link PythonContext#isNativeAccessAllowed()} is {@code false}.
     */
    public static NativePointer createNull() {
        return new NativePointer();
    }

    @ExportMessage
    public boolean isPointer() {
        return true;
    }

    @ExportMessage
    public long asPointer() {
        return ptr;
    }

    @ExportMessage
    public boolean isNull() {
        return ptr == 0;
    }

    @Override
    public String toString() {
        CompilerAsserts.neverPartOfCompilation();
        return String.format("<0x%016x>", ptr);
    }
}
